An Investigation of Building Information Modeling Application in Design-Bid-Build Projects

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An Investigation of Building Information Modeling

Application in Design-Bid-Build Projects

Navid Sanei Sistani

Submitted to the

Institute of Graduate Studies and Research

in partial fulfillment of the requirements for the Degree of

Master of Science

in

Civil Engineering

Eastern Mediterranean University

January 2013

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Approval of the Institute of Graduate Studies and Research

Prof. Dr. Elvan Yılmaz Director

I certify that this thesis satisfies the requirements as a thesis for the degree of Master of Science in Civil Engineering.

Asst. Prof. Dr. Mürüde Çelikağ Chair, Department of Civil Engineering

We certify that we have read this thesis and that in our opinion it is fully adequate in scope and quality as a thesis for the degree of Master of Science in Civil Engineering.

Asst. Prof. Dr. Alireza Rezaei Supervisor

Examining Committee 1. Prof. Dr. Tahir Çelik

2. Prof. Dr. Özgür Eren

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ABSTRACT

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ÖZ

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ACKNOWLEDGEMENTS

I would like to acknowledge my dear supervisor Dr. Alireza Rezaei for supporting my Master thesis research. His guidance helped me in all aspects of research and writing of this thesis. I owe him for my experiences in research.

Beside my advisor, I appreciate Prof. Dr. Tahir Çelik who shed light for me in construction management. He made opportunities for me to working in this area. My sincere thanks go to Dr. Ozan Koseoglu for introducing BIM to me.

I thank specially to my dear friend, Mohamadreza Zadeh Morshedbeik, for sharing his knowledge about planning and scheduling with me.

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LIST OF TABLES

Table 4.1. Companies’ size in terms of maximum cost and number of projects ... 45

Table 4.2. Contractual details of studied case ... 47

Table 4.3. Specifications of studied case ... 48

Table 5.1. Quantities and costs in bidding documents and BIM models ... 60

Table 5.2. Rework related costs ... 63

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LIST OF FIGURES

Figure 1.1. Research process... 4

Figure 4.1. Breadth versus depth in 'question-based' study ... 40

Figure 4.2. Percentages of respondents in terms of size of their companies ... 45

Figure 5.1. Level of familiarity with BIM ... 52

Figure 5.2. Effects of BIM on construction management factors ... 53

Figure 5.3. Level of effectiveness of barriers to adopting BIM ... 54

Figure 5.4. Level of effectiveness of challenges in using BIM ... 55

Figure 5.5. Answers to "Do you tend to using BIM in your future projects?" ... 56

Figure 5.6. Autodesk Revit Architecture Model ... 57

Figure 5.7. Autodesk Revit Structure Model ... 57

Figure 5.8. Sample of quantities report in Autodesk Revit Structure ... 59

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LIST OF ABBREVIATIONS

AEC Architecture, Engineering, and Construction

AGC Associated General Contractors of America

AIA American Institute of Architects

AISC American Institute of Steel Construction

BIM Building Information Modeling

CAD Computer-Aided Design

CO Change Orders

CPM Critical Path Method

DBB Design-Bid-Build

GPS Global Positioning Systems

HSS Hollow Structural Section

HVAC Heating Ventilation and Air Conditioning

IFC Industry Foundation Classes

IPD Integrated Project Delivery

MEP Mechanical, Electrical, and Plumbing

PDM Project Delivery Method

PDS Project Delivery System

RFI Request For Information

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Chapter 1

1 INTRODUCTION

1.1 Introduction

Design-Bid-Build (DBB) is also known as “Traditional” project delivery method. In DBB owner has separate contract with designer and contractor. Designer is responsible to prepare drawings, specifications and bid documents based on the owner’s needs. Then competitive bidding will be held to select the contractor based on the lowest bid price for all work required to build the project as specified in bid documents. After construction industry experienced long term use of DBB, the deficiencies of this method appeared.

BIM which refers to Building Information Modeling initially was considered as a tool for design with components instead of lines. It enabled designers to virtually build a wall with all of its components rather than drawing wall with a series of lines which were used in 2D CAD. But now, BIM is extremely developed to efficient tool for model analysis, clash detection, product selection, and project conceptualization. While BIM involves all project parties rather than just designers, it is a beneficial tool not only for design team, but also for construction industry even whole world.

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is obvious that late involvement of contractor in projects will remain as main disadvantage of DBB method, but some disadvantages of this late involvement can be avoided by using collaborative tools like BIM. Investigating BIM application in DBB projects as a starting point for adopting BIM through construction industry, and also to evaluate its benefits in most popular delivery method seem essential.

Two methods for achieving these aims were employed for gathering both breadth and in-depth information. Questionnaire survey evaluated construction industry practitioners’ opinions about using BIM in DBB projects and through case study benefits of BIM application were calculated simultaneously.

According to the results, the claim of respondents about effects of BIM on reducing cost and time in DBB projects were approved and their corresponded monetary amounts were calculated by case study. Findings showed that using BIM could reduce owner’s costs and contractor’s expenses. In addition BIM usage could avoid delays considerably.

1.2 Statement of the Problem

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Kuprenas and Nasr (2007)conducted a research on cost performance of DBB project delivery. Hallowell and Toole (2009) provided contemporary DBB model .Different project delivery methods were compared by Neil and Al-Battaineh (2011) and impact of design cost on DBB project performance was investigated (Shrestha and Mani, 2012). Previously, benefits, risks and challenges of BIM were analyzed (Azhar, Hein, and Sketo, 2008), profits of scheduling, estimating, and BIM combination were specified (McCuen, 2008) and business value of adopting BIM was demystified (Aranda-Mena et al., 2009). Gu and London (2010) surveyed BIM adoption in the AEC industry. Becerik-Greber and Kensek (2010) specified research directions and trends about BIM. Benefits of BIM was investigated by Azhar (2011) and was measured by Barlish and Sullivan (2012).

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Figure 1.1. Research process (Fellows and Liu, 2009)

1.3 Aims and Objectives

To achieve the aim of this study which was answering to determined research question, following objectives were defined:

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2. To specify most significant barriers to adopting BIM in DBB projects. 3. To determine most significant challenges in using BIM in DBB projects. 4. To calculate the amount of cost saving by using BIM in DBB projects.

5. To compute the amount of delays that can be avoided by using BIM in DBB projects.

1.4 Works Carried Out

To investigate BIM application in DBB projects, the Triangulation Mixed-Method that uses two research methods simultaneously was selected for this study. By questionnaire survey, effect of using BIM on factors of construction management diamond -time, cost, quality, and health and safety- were evaluated. Afterward, most significant barriers to adopting and challenges in using BIM were specified by respondents. Finally, respondents expressed their tendency to participate in BIM training and using BIM in their future projects. According to characteristics of case study which encourages in-depth investigation of particular instances within the research subject, a single-case were studied to investigate effects of using BIM on cost and time of DBB projects.

1.5 Achievements

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According to case study, it was found out that by reducing initial estimated cost and avoiding change orders by using BIM, owners could save at least 9.6 percent of total project cost and contractor could reduce his/her expenses at least 5.9% of total project cost. Change orders and reworks resulted from inaccuracies of design, totally caused 21 days delay in project completion equal to 17% of total project duration which was avoidable by using BIM.

1.6 Limitations and Delimitations

While this study was delimited to DBB projects in Iran and questionnaires were filled out by construction industry practitioners in Tehran (capital of Iran) and Mashhad (second largest city of Iran), the followings are undesirable limitations of this study:

 Low level of awareness about BIM among respondents which might cause to doubt on reliability of questionnaire results.

 Hardware limitations caused by inefficiencies of computer which was used for modeling the studied case.

 Software limitations caused by using student version software for modeling the studied case.

 Limitations caused by inaccuracy or lack of information about the reasons of cost overruns and delays in studied case.

1.7 Thesis Guideline

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associated with DBB are mentioned. Finally, importance of studying this method regarding to its characteristics is exlained.

Chapter 3 aims to define BIM and describe its differences with CAD. Advantages of using BIM for owners, designers, and contractors are discussed, challenges in adopting and using BIM are described and finally, significance of BIM as subject of this study according to its advantages is summarized.

In chapter 4, review of literature represents methods used in previous researches with the similar topics of this study and reasons for choosing each method in this research. Questionnaire survey is then described from designing and distributing to respondents’ information. Finally, general information and contractual details of studied case and software used for modeling are explained.

Chapter 5 discusses on questionnaire survey, participants’ point of view about level of effectiveness of BIM on construction management factors, barriers for adopting BIM, challenges to using BIM, and their consideration about BIM. In accordance to studied case, effects of using BIM in reducing cost and time in a DBB project are evaluated. Finally, results of this study are summarized.

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Chapter 2

2 DESIGN-BID-BUILD

2.1 Introduction

Although there are different types of methods for delivering projects, no one is perfect for all types of projects and regarding to their advantages and disadvantages, each one is appropriate for specific project. This chapter introduces Design-Bid-Build (DBB) as one of the most important project delivery methods.

In this chapter, Project Delivery Method (PDM) or Project Delivery System (PDS) is defined in the second section. Third section describes DBB, and discusses roles and responsibilities of owners, designers, and contractors, and mentions advantages, disadvantages, and risks associated with DBB. Finally, summary section explains importance of studying this method regarding to its characteristics.

2.2 Project Delivery Methods

Kenig (2004) mentioned owner, designer, and contractor as ‘classic triangle of construction’ which participate in all projects. Variety of their relationships shape different PDMs. “Project delivery method is the comprehensive process of assigning the contractual responsibilities for designing and constructing a project” (Kenig, 2004).

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activities required to complete a project” (Walewski, Gibson, and Jasper, 2001). Ohrn and Rogers (2008) defined PDM as “the process through which constructed projects are organized and completed including establishing how the contractor will be selected, the scope of services provided, the type of relationship with owner, and how the contractor will be compensated”.

Cost, quality, time, and safety are four considerable factors in managing any construction project which could be achieved by different methods. Performance, trust and cooperation among parties are factors of success or failure of delivery methods. Regarding to uniqueness of every project, each project has its own particular challenges which lead to establish the claim that ‘there is no perfect project delivery’. Therefore, selecting the best project delivery method for each project must be performed separately case-by-case (Mahdi and Alreshaid, 2005).

Jackson (2010) stated that “project delivery methods differ in five fundamental ways:

 The number of contracts the owner executes,

 The relationship and roles of each party to the contract,

 The point at which the contractor gets involved in the project,

 The ability to overlap design and construction,

 Who warrants the sufficiency of the plans and specifications”.

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construction firms which led to appearance of DBB project delivery method. Seeking qualification from architects and engineers by federal government as largest purchasers of construction services and demanding to deliver projects based on low bid were two side of the coin which solidified basis of using DBB. Using DBB was continuing for about 150 years (Greenhalgh, 2011).

After construction industry experienced this long term use of DBB, the deficiencies of this method appeared. Linear sequence of design and construction due to necessity of completing design prior to starting construction which leads to time-consuming process of delivery, also detecting design failures that resulted in Request For Information (RFI) or Change Orders (CO) which caused disputes and aggressive atmosphere between different participants were examples of this delivery method defects (Pishdad-Bozorgi and Garza, 2012). To eliminate these defects “the 1996 Clinger-Cohen Act allowed qualifications-based selection of builders using the design-build and construction manager as constructor forms of project delivery” (Smith, Castro-Lacouture, and Oberle, 2009) and alternative delivery methods were risen up.

2.3 Design-Bid-Build

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authority to use an alternative method for a special project, a group of states have put some limits on the application of alternative delivery methods, and a few states require obtaining extra approval in order to use alternative methods”.

In DBB owner has two separate contracts with designer and contractor. Designer has responsibility to prepare drawings, specifications and bid documents which regard to owner’s needs. Then competitive bidding will be held to select the contractor based on the lowest bid price for all work required to build the project as specified in bid documents (Ohrn and Rogers, 2008). The designer may act as the owner representative to control implementing project by contractor but there is no contractual relationship between designer and contractor. According to the nature of this PDM, bidding cannot be performed before completing the design phase because contractor needs completed drawings and specifications to estimate the bid price. So, it is a linear process which contractor and designer integration is impossible (Kymmell, 2008). Touran (2009) mentioned main characteristics of DBB as follows:

 “There are separate contracts for design and construction.

 Contractor selection is based entirely on cost.

 Design documents are 100% complete.”

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Eastman et al. (2011) mentioned six reasons which during construction phase may cause to change in designs:

 “Previously unknown errors and omissions,

 Unanticipated site conditions,

 Changes in material availabilities,

 Questions about the design,

 New client requirements,

 and new technologies”.

Whatever was the reason of changes, these challenges required to be met by project participants. In order for each of above reasons to occur, the process of specifying the cause of change, assigning responsibilities, calculating time and cost, and finding solution must be carried out. This process involves a RFI which must be considered by designer or responsible party, then to issue the CO to all parties. As previously discussed, this process leads to increasing time and cost and probably the disputes and claims.

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13 2.3.1 Owner roles and responsibilities

During the design phase, owners are responsible to describe their needs and expectations from project and provide the requirements to the designers (Mahdi and Alreshaid, 2005). In construction phase, owners have more responsibilities in comparison to design phase. Owner is responsible for interpreting the contract, drawings, and specifications to contractor; also owner must warrant the sufficiency of drawings and specifications for contractor to complete the project. If there are any errors or differences between drawings and owner’s needs, the owner has liability to pay cost of extra tasks which is performed by contractor (Jackson, 2010).

Kenig (2004) stated that “although the owner warrants the design and specifications to the constructor, the designer does NOT warrant the design and specifications to the owner. If the designer makes a design error that costs the owner damages, the designer will be liable to the owner only if the error occurred because the designer failed to perform in accordance with the standard of care and skill applicable to the profession at large.”

2.3.2 Designer roles and responsibilities

Designer’s responsibilities are to design drawings and specifications together with assisting the owner to prepare bid documents. Kenig (2004) mentioned that the designers have two types of duties to owners:

 Duties created by a professional standard of care expected from the designer or engineer,

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Professional standard of care duty is about performing the design at the level which expected from any member of architectural or engineering profession. The standard of care is not addressed in contract and may be established by government or the profession itself.

According to the contract, designer also has duties to prepare drawings and specifications considering the requirements stated in contract (Kuprenas and Nasr, 2007). These duties are in addition to professional standard of care duties and may include scheduling, cost, and approvals.

2.3.3 Contractor roles and responsibilities

The main responsibility of contractor is to perform the minimum requirements of contract to satisfy the owner. In the bidding stage, owner seeks for the least bid price; so the contractor undertakes implementing project with the minimum requirements expressed by drawings and specifications. Of course, owner has this right to ask further tasks by change orders. The contractor accepts the risk of performing project by the bidding price and is free to complete the project by its own means and methods.

2.3.4 Advantages

The most significant advantages of DBB method are as listed below:

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are uncertainties about the quantities, using the unit price method can deliver benefit to owner and contractor does not suffer from risk of fluctuating quantities.

Competition: According to high amount of qualified contractors, in comparison with alternative delivery methods, DBB has highest level of competition (Walewski et al., 2001). This market competition is profitable for owner by receiving proposals with low bid price. There is a potential for owner to increase competition by dividing project to small packages and assigning several contractors for each part (Touran et al., 2009). In addition, this delivery method is very useful for public owners to assign the contractor neutrally and without any political pressure or corruption (Kenig, 2004).

Experience: The DBB historically used by contractors and their experiences in this delivery method made it the best option in terms of contractor experience (Harrington-Hughes, 2002). As this method is known as a traditional delivery method, it is well understood by different parties of construction industry; also considering staff capabilities, experiences in using DBB are significant.

Goals and Objectives: Full control of owner on design phase and completing design prior to commencing construction phase ensure owner to achieving the goals and objectives of the project (Touran et al., 2009).

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mentioned in bid documents. This method has also a well-known procedure for change orders which makes it flexible during construction phase.

Third-Party Agreements: In DBB method, owner has enough time to negotiate with stakeholders and get required agreements before construction phase. Stakeholders are also able to control the completed design prior to assigning contractor.

Laws: Historical usage of this method during last 150 years provided well-structured legal basement for using DBB worldwide. Regarding to selecting contractor by bidding, it is the most reliable method for delivering projects and there is familiarity for authorities in dispute conditions.

Sustainable Design Goals: This method allows owner to consider social and environmental impacts of project and makes opportunity to have a sustainable design. These goals can be achieved by applying recycled materials and including stakeholders inputs into design phase (Touran et al., 2009).

2.3.5 Disadvantages

As previously stated, DBB has disadvantages which were recognized by reviewing the literature and will be described in the following:

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method has also longer schedule growth in comparison with other delivery methods (Scott et al., 2006).

Staffing Required: Regarding to the characteristics of this delivery method, owner has two separate contracts with designer and contractor. The owner deals with designer at the beginning and then with contractor in construction phase. The high level of involvement in different phases of project needs employing a large number of staff by owner (Kenig, 2004).

Complete Design: Completing design prior to construction phase results in lengthy design phase because of high amount of stakeholders inputs and also lead to lack of contractor inputs in design phase (Touran et al., 2009).

Construction Claims: DBB is in first level in terms of high number of claims and disputes. The subject of disputes are authority, responsibility, and quality (Walewski et al., 2001). While the owner is responsible for accuracy of designs, the error claims is prevalent in DBB. Konchar and Sanvido (1998) expressed that one indication of the high number of claims is possibly the highest amount of cost growth in this delivery method.

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Communication: Involvement of contractor into project after completing design phase and lack of early communication may lead to oversights and misunderstanding about the project details (Kymmell, 2008). In more crucial circumstances, Pishdad-Bozorgi and Garza (2012) mentioned ‘lack and/or failure of collaboration and communication among the parties’ as one of the reasons which creates adversarial relationships amongst and between project participants which results in litigation between them.

Change Orders: While the owner is responsible for accuracy of design, in case of encountering with errors in design, owner is liable to financing the changes. Because of this there is no incentive from contractor to decrease the cost of change orders in DBB (Touran, et al., 2009).

Bid Price: One of the most popular issues in failure of DBB projects is offering underestimated price to win the bid. In this condition, contractor tries to compensate the losses by profiting from change orders. This abuse of change orders increases disputes between owner and contractor (Eastman et al., 2011).

Errors: During design phase, errors may rise up because of different reasons. The reasons may be unintentional like human errors or carelessness, or purposeful like including fewer details in drawings to enhancing more profit from reallocating design cost.

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associated with this delivery method to lose sustainable certificates like LEED (Touran et al., 2009).

2.3.6 Risks

In DBB method, owner can divide risk between designer and contractor, but errors in design may result in cost overrun which owner shifts this risk to designer team. This delivery method had used for more than one century, this long term usage provided rich background in terms of laws and standard contract to managing risks associated with DBB. Walewski et al. (2001) noted that “although risks and rewards are easy to understand in this method, disputes often arise over authority, responsibility, and quality.”

Owner may or may not gain profit from separate contracts with designer and contractor depending on the experience of owner and its consultant in managing risks. The most important factor in successful managing of risks in this delivery method is to clearly define scope of project and works in designer and contractor contract. Otherwise the owner encounters with challenges resulting from uncertain duties and responsibilities.

2.4 Summary

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Chapter 3

3 BUILDING INFORMATION MODELING

3.1 Introduction

Recently, advanced technology in construction industry called Building Information Modeling (BIM) became popular among construction industry. The main questions about BIM are “What are its differences with 3D CAD?” and “What advantages do these differences provide in comparison with CAD?”

In this chapter, second section tries to define BIM and describes its differences with CAD. Next three sections discuss about advantages of using BIM for owners, designers, and contractors. Then, challenges in adopting and using BIM are described and finally, significance of BIM as subject of this study according to its advantages is summarized.

3.2 What Is Building Information Modeling?

3.2.1 Definition

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BIM was considered as a tool for design with components instead of lines. It enabled designers to virtually build a wall with all of its components rather than draw wall with a series of lines which were used in 2D CAD. But now, BIM is extremely developed to efficient tool for model analysis, clash detection, product selection, and project conceptualization (Weygant, 2011).

Eastman et al. (2011) claimed that “Building Information Modeling (BIM) is one of the most promising developments in the Architecture, Engineering, and Construction (AEC) industries that results in better quality buildings at lower cost and reduced project duration”. Also, Weygant (2011) emphasized “this advancement (BIM) created one of the largest cost benefits that the design and construction communities have ever experienced”.

3.2.2 BIM versus CAD

“Just as CAD (computer-aided design) improved upon hand drafting, BIM is improving upon CAD. To put it simply, CAD + specifications = BIM” (Weygant, 2011).

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Unlike the general belief, 3D design and visualization is not the main characteristic of BIM, while nowadays most of the simple CAD software comprises this ability. The main difference of BIM and CAD is that despite the CAD drawings which are built with lines, in BIM, components are intelligent and contain their own details such as size, material, type etc. Jackson (2010) stated “because of the ‘I’ in BIM, the model can expand beyond the 3D features that allow the architect to communicate the design intent and lets us see the project. The ‘I’ permits us to add the fourth and fifth dimensions of time and cost to the BIM”. While BIM involve all project parties rather than just designers, it is a beneficial tool not only for design team, but also for construction industry even whole world.

3.2.3 Misconceptions regarding BIM

Like every new tool and technology, BIM also has its pros and cons which insist on their reason. Some of these oppositions are based on misunderstandings about BIM and its concept. Deutsch (2011) mentioned some of most important misconceptions about BIM as follow:

 “Productivity suffers during the transition to BIM.

 BIM applications are difficult to learn.

 BIM disrupts established workflows.

 Owners and contractors benefit most from BIM, not the designer.

 BIM increases risk.

 BIM requires a different project delivery method.

 You cannot tell who is responsible for what or who owns the model.

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 BIM blurs the distinction between design and construction.

 The architect is not in “responsible charge” of the design.

 You cannot have some information in the model and some only in 2D details.

 The model cannot be a contract document.

 You cannot rely on the dimensions of the model.

 The architect is subject to more lawsuits from contractors.”

3.2.4 BIM adoption

It must be noted that transition from CAD to BIM is a long-term process. Although the obvious advantages of BIM in reducing cost and time and improving quality and health and safety caused that designers moving to use BIM at least two times faster than transition from hand drawing to CAD (Deutsch, 2011), but this transition has been slower than anticipated. Deutsch (2011) noticed that “adopting BIM without a plan can be like taking a trip unaware of all the baggage that can slow you down. Firms may own the software but not yet own the process”.

3.3 BIM for Owners

The owners can benefit from using BIM in several aspects to reduce cost and time and improve quality and health and safety. All types of ownership of almost all types of projects can achieve benefits from using BIM; it is obvious that the amount and types of these benefits differ from case to case. In this section, the most important advantageous criteria of using BIM for owners will be mentioned.

3.3.1 Design assessment

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using 2D drawings and specifications, it will be difficult for owners to assure that projects’ functional needs will be met or not (Nam-Hyuk et al., 2008).

Using 3D modeling will make very easier to involve valuable inputs form all stakeholders into project model. Applying changes to designs regardless of the reason of those changes is much faster and easier in BIM model and will be accessible by relevant stakeholders (Wong, Wong, and Nadeem, 2010). Also in terms of demand for additional types of simulation like crowd behavior or emergency evacuation scenarios, these simulations and relative analysis are accurately performed by BIM model (Becerik-Gerber eet al., 2012).

3.3.2 Complex building

Regardless of project type, design outputs must satisfy the minimum requirements of building code and statutory and liability issues. In modern buildings with complex facilities, these issues are became more complicated especially for Mechanical, Electrical, and Plumbing (MEP) systems (Bernstein and Pittman, 2004).

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26 3.3.3 Sustainability

Nowadays sustainability becomes popular between owners regarding to its three main aspects. Reducing environmental effects of projects is been taken into consideration by society and may increase the marketability of projects; meanwhile energy consumption analysis can reduce the life cycle cost of projects. Selecting most appropriate materials by analysis of efficient energy consumption during design phase is one of the most significant advantages of using BIM (Bynum, Issa, and Olbina, 2012).

3.3.4 Cost estimate

One the most popular problems which owners in construction industry may face is cost overruns. Main reasons of cost overruns are inaccurate design and unreliable estimates. Jackson (2002) mentioned four reasons which impact estimates reliability as market conditions that change over time, the time between estimate and execution, design changes, and quality issues. BIM provides the basis for accurate estimate by detailed quantities and enables owner to influence project cost at the early phases like conceptual and feasibility phases. Employing BIM at early phases allows owners to compare different design scenarios. “Accurate estimates can be very valuable early in the project, particularly for assessing a project’s predicted cash flow and procuring finance” (Eastman, et al., 2011).

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omissions. Additionally, the more accurate derivation of components that BIM provides does not deal with specific site conditions or the complexity of the facility, which depend on the expertise of an estimator to quantify. BIM-based cost estimation strategically helps the experienced cost estimators but does not replace them.”

3.3.5 Time reduction

Time delays are bottleneck for all delivering products in all industries; construction industry is not exempted in having trouble with delays in project delivery. BIM help owners and project team to reduce time at all phases by several ways (Harty and Laing, 2009). Parametric nature of components in BIM makes prefabrication easier and provides automated update after design changes which leads to faster project completion (Barlish and Sullivan, 2012). Using BIM can increase productivity by providing better understanding among project practitioners. Increasing productivity has positive effects on reducing scheduled times of the tasks.

By integrating 3D BIM model with time scheduling, 4D model will be produced that links the components with their corresponding tasks. 4D modeling gives better understanding about the tasks and their relationships and sequences result to more reliable schedule and plan for construction phase. During the construction phase, it is very valuable to virtually compare the real completion percentage of project with anticipated one according to schedule (Chau, Anson, and Zhang, 2004).

3.3.6 Facility management

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also be in usable form for facility managers. Using BIM gives more reliability to owners in commissioning phase to be sure that their operational needs were met. By transition information from whole practitioners to facility manager as BIM model, extra efforts for gathering project data will be avoided and will be resulted to save time and cost. BIM model also can use to assess how maintenance operations and activities in one section affect other sections (Park et al., 2011).

3.4 BIM for Designers

“Building Information Modeling (BIM) can be considered an epochal transition in design practice” (Eastman, et al., 2011). BIM affected all stages of design including conceptual design, architectural design, engineering analysis, and construction-level design. While BIM influences design phase more than other phases, the advantageous using of BIM during design phase is divided into three stages and is described in following.

3.4.1 Design

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Synchronizing different software data is practicable by new neutral format called IFC (Industry Foundation Classes: an industry-developed product data model for the design and full lifecycle of buildings, supported by building SMART. It has broad support by most software companies) (Fu et al., 2006). Additional requirements like fire safety, access for the disabled also can be met by using BIM (Becerik-Gerber et al., 2012).

Designers are responsible not only to prepare drawings and specifications, but also to estimate construction cost to assure owner that project cost will not be more than allocated budget. Cost estimating was traditionally performed by multiplying quantities calculated from volumes and areas represented by lines in drawings to unit prices of items described in specifications. All these calculations were done by human and like any other human activities contain mistakes and errors. According to component-based nature of BIM, quantity takeoff is calculated automatically considering the amount of specific materials defined in BIM model. These accurate quantities lead to precise estimated cost for materials and products (Hartmann, Gao, and Fischer, 2008).

Simulation can be very useful for projects needing special attention to spaces and crowd like manufacturing, hospitals, and airports. In these cases, project functions strongly depend on spaces for machinery operation, equipment and personnel activities, or crowd movement. BIM enables designer to evaluate required spaces for efficient function of buildings (Becerik-Gerber et al., 2012).

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needs to be reviewed to gaining feedback, advice, or changes. In traditional methods this process was performed by meeting in presence of representatives of all stakeholders which was time-consuming and difficult to arrange. Nowadays, each expert firm is able to design their specific elements (e.g. structual or mechanical systems) by professional software which will be integrated together by designer team. The clashes between different systems and elements which were designed separately are detectable by ability of BIM software called “Clash Detection” (Love et al., 2011).

3.4.2 Construction model

Eastman et al. (2011) mentioned three approaches of designers against developing construction model:

1. Traditionally, the design outputs expressed only the intent of designer and owner. In this approach, contractors must develop their own independent model for construction based on drawings and specifications.

2. Designers provide detailed model for further usage in construction, planning, and fabrication. Design model is initiative for developing special model of construction.

3. Collaborative approach which involve designer, contractor, supplier, fabricator, etc. from early design phase. The model is representative of all stakeholders’ input data.

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each of these services delivered by separate organizations, using BIM has notable influences on collaboration between these organizations.

BIM model also can be used as legal and contractual source of information instead of 2D drawing s and specifications. For example, American Institute of Steel Construction (AISC) in its standard stated that in terms of representing structural steel of project in both types of model and drawings, the model will be design of record. Widespread adoption of BIM by varied institutes into their standards is anticipated according to advantage of BIM in better understanding about details (Eastman et al., 2011).

3.5 BIM for Contractors

By using BIM model, contractor can save time and money by reducing errors and reworks. “While some of the potential value of a contractor’s knowledge is lost after the design phase is complete, significant benefits to the contractor and the project team can still be realized by using a building model to support a variety of construction work processes. These benefits can ideally be achieved by developing a model in-house with the collaboration of subcontractors and fabricators” (Eastman et al., 2011). In this section the advantages of using BIM for contractor will be briefly explained.

3.5.1 Clash detection

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Depending on level of defined information in BIM model, different types of clash detection can be performed. “Soft clash” detection may vary from clashes between components in individual system to clashes between different systems like structural and mechanical systems. In well-defined BIM models, “Hard clash” is detectable to assure about sufficient space between components of different systems for adequate access, insulation, safety, or maintenance. For example, spaces between mechanical and structural systems like distances between steam boiler and floor, walls, and roof (Eastman et al., 2011).

3.5.2 Quantity takeoff and cost estimating

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Bar charts were of the first methods created for planning and scheduling the projects which by programmer efforts were transformed to planning software like Microsoft Projects and Primavera P3. These software known as Critical Path Method (CPM) software, enable planners to create and update tasks and define their relationships and sequences and calculate critical paths and floats (Ospina-Alvarado and Castro-Lacouture, 2010). Although these software have substantial excellence in comparison with bar charts, they are associated with some deficiencies in visualization of activities or linking with design or building model. As long as the CPM software remain solitary, it will be difficult for stakeholders to understand schedule and project progress. 4D model results from adding time as fourth dimension to 3D model which can be created easily by using BIM and lead to comprehensible scheduling.

3.5.4 Project control

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Contractors prefer to reduce costs and risks associated with labor and improve quality by using prefabricated or offsite fabrication components. Today, widespread range of components are produced in factories and deliver and assembled or apart to project sites for installation (AGC, 2009). However, using prefabrication requires precise planning and accurate design details which is not possible easily by 2D drawings. In addition to accurate design information, BIM enables contractors to enter 3D geometry, material specifications, finishing requirements, delivery sequence, and timing before and during the fabrication process (Rowlinson et al., 2010). Early involvement of fabricator and subcontractors in preparing BIM model reduces time by verifying and validating the model instead of paperwork required in terms of using 2D drawings.

3.5.6 Onsite usage

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35 3.5.7 Lean construction

“Lean is a way to design production systems to minimize waste of materials, time, and effort in order to generate the maximum possible amount of value” (Best and De Valence, 2002). The Construction Industry Institute (CII) (2005) defined lean construction as “the continuous process of eliminating waste, meeting or exceeding all customer requirements, focusing on the entire value stream, and pursuing perfection in the execution of a constructed project.”

Eastman et al. (2011) mentioned four areas for synergy of BIM and lean construction:

 Use of BIM reduces variation.

 BIM reduces cycle times.

 BIM enables visualization of both construction products and processes.

 BIM supports a number of lean principles in the design stage.

3.6 Challenges

Using BIM needs changes in all aspects of construction industry from skills of practitioners to relationships and contractual agreements between them. During this transition construction industry faces with different challenges. In this section, most notable expected challenges will be described.

3.6.1 Legal issues

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and the Associated General Contractors of America (AGC) address these issues and make efforts to cover them by providing contractual guidelines like “ConsensusDOCS 301 BIM Addendum”.

3.6.2 Collaborating issues

The most significant collaborative issue is software interoperability. Although the IFC format facilitates using BIM software, some problems still arise according to using different software or even different versions of individual software. Another solution for this problem is using model server which contains its own difficulties considering network security, define accesses and permissions for different users and etc. If design teams do not create a BIM model, the contractors must develop their own model which could be time-consuming and costly. Even if the designers use BIM, their model may do not contain sufficient details for utilization in construction phase. These issues are challenging and can harm to collaboration among project participants (Fallon and Palmer, 2007).

3.6.3 Procedure change issues

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3.7 Summary

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Chapter 4

4 METHODOLOGY

4.1 Introduction

To achieve research objectives, selecting proper research method must be performed. Selection of research method in this study is based on review of previous research studies, specifications of each method, available resources (cost and time), and existed limitations and delimitations.

In this chapter after introduction, review of literature represents methods used in previous researches with the topics similar to this study and reasons for choosing each method in this research. Second section comprehensively describes questionnaire survey from designing and distributing questionnaires to respondents’ information. Finally, general information and contractual details of studied case and software used for modeling are explained.

4.2 Review of Literature

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(Korkmaz, Riley, and Horman, 2010). Using case study, Different project delivery methods were compared by Neil and Al-Battaineh (2011).

Case study was also utilized to investigate impact of design cost on DBB project performance (Shrestha and Mani, 2012).

Benefits, risks and challenges of BIM were analyzed by reviewing previous surveys and studying a case (Azhar, Hein, and Sketo, 2008). Case study was also used to specify profits of scheduling, estimating, and BIM combination (McCuen, 2008) and to demystify business value of adopting BIM (Aranda-Mena et al., 2009). Gu and London (2010) surveyed BIM adoption in the AEC industry; also Becerik-Greber and Kensek (2010) specified research directions and trends about BIM by questionnaire. Using case study, benefits of BIM was investigated by Azhar (2011) and was measured by Barlish and Sullivan (2012).

According to the review of literature, for subjects of this study, Design-Bid-Build delivery method and Building Information Modeling, case study and survey (especially questionnaire) were found to be the most appropriate and popular methods among researchers.

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The questionnaire is one of the most popular and valuable instruments of data collection (Lavrakas, 2008). Questionnaires can be used even in cases which respondents are not completely aware of the subjects (Bryman, 2008). “If the questionnaire is well constructed, processing the data can also be fast and relatively straightforward, especially by using some modern computer software.They are also very versatile, which means that they can be used successfully with a variety of people in a variety of situations targeting a variety of topics” (Dörnyei and Taguchi, 2010).

Figure 4.1 shows different areas which each type of study covers. “A particular management research project may require and involve more than one method of data collection. The different research methodologies and techniques are simply a set of tools that the researcher can use to address the particular consultancy and research problem” (Lancaster, 2005). Considering these issues, it was decided to use a mixed-methods research design consisted of case study and questionnaire survey.

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Between types of mixed-methods research design, which differ from each other in terms of sequence of using methods, the Triangulation Mixed-Methods Designs was selected for this study. Triangulation uses two or more research methods simultaneously to investigate the same thing (Fellows and Liu, 2009; Lavrakas, 2008).

4.3 Questionnaire Survey

As previously stated, a questionnaire survey as a part of compounded methodology was conducted among construction industry practitioners. As Brown (2001) defined, “questionnaires are any written instruments that present respondents with a series of questions or statements to which they are to react either by writing out their answers or selecting from among existing answers.”

4.3.1 Design of questionnaire

A questionnaire including closed-ended questions was designed based on the literature review to answer the research questions. A sample questionnaire is appended in Appendix A. “A closed-ended survey question is one that provides respondents with a fixed number of responses from which to choose an answer. It is made up of a question stem and a set of answer choices (the response alternatives)” (Lavrakas, 2008).

The questionnaire was divided into four main segments:

 Personal information

 Knowledge and experiences of BIM

 Definition of BIM, and

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The first part was consisted of closed-ended questions to find out respondents personal information by selecting among nominal categories. These questions were about the parties of construction industry which respondents were involved, and were separated into: owner, designer, and contractor. Then the level of their company, in terms of maximum number and cost of the projects that annually they are permitted to execute, was asked. Finally, they categorized their job experience into: less than five years, between five and ten years, between ten and fifteen years, and more than fifteen years.

In second part, knowledge of BIM was asked by this question; “How much are you familiar with Building Information Modeling?” Respondents chose between following four choices: “Not familiar”, “Just heard its name”, “A little familiar”, and “Absolutely familiar”. The experience of using BIM was determined by a question with two options: “Yes, I used”, and “No, I did not use”.

Regarding to low level of awareness about BIM among Iran’s construction industry practitioners which was found out in previous study by Sistani and Rezaei (2012), a brief definition of BIM was presented in the third part. In addition to definition of BIM, most important advantages of using BIM like clash detection, differences of BIM with 3D CAD, properties of projects designed by BIM, and two of most popular BIM software (GRAFISOFT ArchiCAD and Autodesk Revit) were given in this part for better understanding of BIM.

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selecting one of the categorized alternatives. The categorized alternatives indicate different degrees of a certain category (Dörnyei and Taguchi, 2010). Alternatives ranged in Low-to-high sequence which indicated a unipolar conceptualization, whereby the low end represented the absence of the concept of interest and the high end represented a great deal, in this case expressed the effect, from ineffective to extremely effective (Lavrakas, 2008).

Respondents’ opinions about the effects of BIM usage in DBB project delivery were asked by four questions. Effect of using BIM on factors of construction management diamond; time, cost, quality, and health and safety were evaluated by respondents, and then in next questions they ordered these factors from most affected to the least.

Afterward, the ratio of effectiveness of shortages which caused to not applying BIM in Iran’s construction industry was determined for five main deficiencies. After these questions, one blank line was placed for another shortage which respondents thought must be in this section, and they could rank its effectiveness as previous questions. As same as the former section, in next section, respondents’ opinions in terms of barriers to using BIM through DBB projects were evaluated. Two last questions were about respondents’ tendency to participate in BIM training and using BIM in their projects.

4.3.2 Testing and validating

For testing the quality of questionnaire, according to Saris and Gallhofer (2007) these three steps were done:

 “Check on face validity

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 Use of a pilot study to test the questionnaire”

For this reason, after checking the face and routing in the questionnaire, 5 graduate students of Construction Management in Civil Engineering Department were asked to fill out the first draft of questionnaire as a pilot study, and then questionnaire was discussed by them one after another. The results of pilot study were analyzed statistically by Microsoft Excel and the standard deviations of the answers were calculated. The highest amount of the answers’ standard deviations was 1.03, which confirmed the answers of questionnaires’ validity. According to discussions with respondents of pilot study, little changes were performed, and then the final questionnaire was completed and distributed.

4.3.3 Respondents

Total numbers of 60 questionnaires were sent to 5 civil engineers and they were requested to distribute them among architects and engineers engaged in construction industry in designer, contractor, or owner parties. The questionnaires were filled out in the way of One-to-One administration by a civil engineer for further assistance.

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Iranian construction companies are divided into five levels according to their size. Respondents were selected from companies with different scales in terms of annual income. Respondents’ distribution in terms of size of their companies is shown in Figure 4.1.The number and cost of projects each company permitted to execute annually is limited for each level (Table 4.1).

Figure 4.2. Percentages of respondents in terms of size of their companies

Table 4.1. Companies’ size in terms of maximum cost and number of projects

Characteristics Size

Maximum costs of projects per year (US Dollar)

Maximum numbers of projects per year

Very Small 650,000 4

Small 1,860,000 3

Medium 3,720,000 3

Large 7,430,000 3

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4.4 Case Study

“A case study is a detailed study of a single individual, group/organization, or event/project” (Fellows and Liu, 2009). The case can be studied by different types of data collection varied from review of records to interview with participants. Hancock and Algozzine (2006) stated that “case study research is richly descriptive, because it is grounded in deep and varied sources of information.” The number of cases depends on different factors, “The nature of the in-depth data collection, limited access to cases, and the extreme nature of the case are reasons for study single case” (De Vaus, 2001; Fellows and Liu, 2009). Based on these three reasons, single-case was studied in this research.

Because of popularity of DBB method among public sector, they are experienced in using this method; so an ordinary office building was selected as a case of this study. This building is client office of a power plant. The reason for selecting this project as case was using steel gable frame consisting of welded columns and beams as structure of this building. Such structure must be fabricated offsite and needs accurate details and experienced technicians for assembly and installation. Since the building was part of a power plant project, the designer and contractor of project were extra-large companies and the owner was Ministry of Energy of Iran. Details and specifications of the project are presented in next section.

4.4.1 Details and specifications

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Table 4.2. Contractual details of studied case

Project Name Thermal Power Plant (2×325 MW) (Client Office)

Owner

MINISTRY OF ENERGY Iran Power Development Co.

(I.P.D.C.)

Designer Ghods Niroo Engineering Company G.N.E.C.

Consultant Energy and Industry Consultants

Contractors

Hirbod Niroo Company

Mabna Niroo Company Azaran Company

Project Delivery Method Design-Bid-Build

Type of Contract Lump Sum

Project Cost 775812 ($)

Project Duration 89 (Workdays) 123 (Days)

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Table 4.3. Specifications of studied case

Area 650 m2

Type of Structure Steel Gable Frame Material of Structure

(Columns and Beams) Plate Girder (Welded Steel) Foundation Type Spread Footing Foundation

Material of Foundation Reinforced Concrete

Exterior Walls

35 cm (20 cm clay brick work + 5 cm Rockwool Inulation +

10 cm Brick Facing) Interior Walls 20 cm (Clay Brick Work)

Supporting Structure of Roof Purlin and Struts with Bracing

Outer Layer of Roof Systems Sandwich Panel

Ceiling Systems Knauf Ceiling

4.1.2 Modeling

To evaluate effects of using BIM on project’s time and cost, the project was modeled by using six software. These software and their usage will be described at following.

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of roof including struts, bracings, and purlins were also designed by Revit Structure. This software only supports the standard steel components (e.g. I-shaped, HSS-shaped (Hollow Structural Section), L-HSS-shaped, C-HSS-shaped, and T-HSS-shaped cross-sections and bars); so for designing the columns and beams, AutoCAD Structural Detailing software was used.

AutoCAD Structural Detailing: In accordance with the structural frame containing plate girders, the detailed columns and beams were designed by 2012 version of this software. AutoCAD Structural Detailing is professionally developed to design uncommon structures providing widespread range of elements and different types of connections. For synchronizing data between AutoCAD Structural Detailing and Autodesk Revit Structure, an extension was installed on Autodesk Revit Structure.

Autodesk Revit Architecture: As it is obvious this software was used for designing architectural components. External and internal walls, doors and windows, flooring and ceiling, and plastering are some examples of the designed components with 2010 version of this software. Autodesk Revit Architecture contains variety of materials and components families to facilitate designing all details in all types of buildings in 3D environment. This software provides walkthrough animations, quantities, and material takeoff as well.

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plumbing components and systems were designed by the 2012 version of Autodesk Revit MEP.

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Chapter 5

5 RESULTS AND DISCUSSIONS

5.1 Introduction

According to the outputs of questionnaire survey and case study, the results were analyzed to evaluate opinions of construction industry practitioners about advantages, barriers of adopting, and challenges of using BIM in DBB projects, then the most notable advantages of using BIM from viewpoint of questionnaire participants was assessed in case study.

This chapter starts with introduction and then regarding to questionnaire survey, participants’ point of view about level of effectiveness of BIM on construction management factors, barriers for adopting BIM, challenges to using BIM, and their consideration about BIM are discussed in second section of this chapter. In accordance with studied case, in third section effects of using BIM in reducing cost and time in a DBB project are evaluated. Finally, results of this study are summarized in last section.

5.2 Questionnaire Survey

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generally speaking, the level of awareness about BIM among construction industry practitioners is evaluated as low.

Figure 5.1. Level of familiarity with BIM

Because of predicted low level of awareness about BIM, a brief definition of BIM and its significant characteristics were jammed into questionnaire to provide little knowledge of BIM to answer further questions.

5.2.1 Advantages

Rate of advantageous effects of using BIM on factors of construction management diamond; cost, time, quality, and health and safety were asked one by one. The question was close-ended with Likert scale answers varied from “No effect” to “Extreme effect”. The weighted means of respondents’ answers to each of these four questions are calculated as shown in Figure 5.2.

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weighted means of first and second factors explains confidence level of respondents about the effects of BIM on this factor.

Figure 5.2. Effects of BIM on construction management factors

“Reduce time” and “Improve quality” are very close with 3.00 and 2.97 weighted means respectively. “Improve health and safety” is placed at the bottom of the list in range of low to medium effect with weighted mean of 2.57. According to the answers to this question, reduce cost and time is considered as the most significant advantages of using BIM in DBB projects and validity of this claim is verified by studying the case which will be discussed later.

5.2.2 Adopting barriers

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legislation and standards, and supply of private sector for BIM are most significant barriers to adopting BIM from respondents’ opinion. Lack of private sector participation in large project is located at the end of list with 3.00 weighted mean.

Figure 5.3. Level of effectiveness of barriers to adopting BIM

While there are not adequate standards and legislation for using BIM, neither public sector demands for using BIM, nor private sector supplies BIM usage. The question “Who must be pioneer in adopting BIM?” reminisce ancient question that “Which came first, chicken or egg?”

5.2.3 Using challenges

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Figure 5.4. Level of effectiveness of challenges in using BIM

As can obviously be seen, lack of specialist in BIM with great difference is located at the top of the list with 3.79 as weighted mean. Interoperability and software issues and lack of collaborative attitude and mutual trust are next significant challenges in using BIM from respondents’ point of view with 3.31 and 3.14 weighted means respectively. Development cost of BIM positions far distance as last challenge in using BIM. Weighted mean of 2.76 is interpretable considering, companies paying initial cost of developing BIM once forever as investment which will be usable in long-term for many projects.

5.2.4 Future of BIM

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future projects?" Figure 5.5 shows the percentages of respondents in terms of their answers to this question.

Figure 5.5. Answers to "Do you tend to using BIM in your future projects?"

While initially 67% of respondents were completely unfamiliar with BIM and only three percent of them experienced using BIM in their projects, after introducing BIM, more than 93 percent expressed that they tend to use BIM in their future projects. This information states, there is high motivation among construction industry for using BIM if the adequate legislation and BIM specialists exist.

An Investigation of Building Information Modeling Application in Design-Bid-Build Projects